This clicker case study is designed to help students understand the basic events in flowering plant (angiosperm) reproduction and appreciate its importance. (Alternation of generations and double fertilization are excluded, but instructors who want to teach those concepts could easily add them using the illustrations provided.) The case tells the story of “Maria,” whose horse has eaten poisonous yellow star-thistle plants in her pasture. Students follow Maria as she consults with an expert to learn how flowering plants reproduce, during which she reviews flower structure, pollination, fertilization, and seed/fruit development. This initial lesson, which describes reproduction in peaches (a relatively simple model), is then applied to yellow star-thistle plants, which have more complex flowers. Once students understand how flowers reproduce, they think about how to interrupt the process at various points, consider the pros and cons, and discuss which strategy would be best to help Maria eradicate the yellow star-thistle plants in her pasture. The case was developed for a college-level class for non-biology majors; no prerequisite knowledge is required. The case could easily be adapted for use at the high school level.